BioMolecular Engineering Research Center, Boston University, 36 Cummington Street, Boston, MA 02215, USA.
Biol Direct. 2010 May 20;5:36. doi: 10.1186/1745-6150-5-36.
This paper is an attempt to trace the evolution of the ribosome through the evolution of the universal P-loop GTPases that are involved with the ribosome in translation and with the attachment of the ribosome to the membrane. The GTPases involved in translation in Bacteria/Archaea are the elongation factors EFTu/EF1, the initiation factors IF2/aeIF5b + aeIF2, and the elongation factors EFG/EF2. All of these GTPases also contain the OB fold also found in the non GTPase IF1 involved in initiation. The GTPase involved in the signal recognition particle in most Bacteria and Archaea is SRP54.
The evolution of translational GTPases of both the Archaea and Bacteria point to the evolution of the ribosome. The elongation factors, EFTu/EF1, began as a Ras-like GTPase bringing the activated minihelix tRNA to the Large Subunit Unit. The initiation factors and elongation factor would then have evolved from the EFTu/EF1 as the small subunit was added to the evolving ribosome. The SRP has an SRP54 GTPase and a specific RNA fold in its RNA component similar to the PTC. We consider the SRP to be a remnant of an ancient form of an LSU bound to a membrane.
本文试图通过参与翻译和核糖体与膜结合的通用 P 环 GTP 酶的进化来追踪核糖体的进化。参与细菌/古菌翻译的 GTP 酶是延伸因子 EFTu/EF1、起始因子 IF2/aeIF5b + aeIF2 和延伸因子 EFG/EF2。所有这些 GTP 酶还包含非 GTP 酶 IF1 中发现的 OB 折叠，该折叠也参与起始。在大多数细菌和古菌中参与信号识别颗粒的 GTP 酶是 SRP54。
1）基于结构域的结构考虑，古菌的延伸因子具有以下进化途径：EF1-->aeIF2 -->EF2。aeIF5b 的进化是后来的事件；2）基于 GTP 酶域拓扑学考虑的细菌延伸因子具有相似的进化途径：EFTu-->IF-->2-->EFG。这些进化序列反映了 LSU 的进化，然后是 SSU，形成核糖体；3）OB 折叠的 IF1 是古老 tRNA 小环的模拟物。
古菌和细菌翻译 GTP 酶的进化都指向核糖体的进化。延伸因子 EFTu/EF1 最初是一种 Ras 样 GTP 酶，将激活的 minihelix tRNA 带到大亚基单元。然后，起始因子和延伸因子将从 EFTu/EF1 进化而来，因为小亚基被添加到不断进化的核糖体中。SRP 具有 SRP54 GTP 酶和与其 RNA 成分中类似 PTC 的特定 RNA 折叠。我们认为 SRP 是一种与膜结合的古老 LSU 形式的残余物。
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